Receiving means



R. w. GEORGE Re. 21,473

RECEIVING MEANS June .4, 1940.

Original Filed. April 27, 1933 6 Sheets-Sheet 1 @WMQ INVENTOR RALPH w. aEORGE ATTORNEY June 4, 1940. R. w. GEORGE RECEIVING MEANS 6 Sheets-Sheet2 Original Filed April 27, 1933 Figs in INVENTOR RALPH w. GEORGEATI'ORNEY sx n? June 1940- R. w. GEORGE V RECEIVING "BANS Original FiledApril 27, 1933 l l I I l l l I I l l 1i l|l l|||| |||||||||||l||||INVENTOR RALPH W. GEORGE ATTORNEY R. w. GEORGE Re. 21,473

RECEIVING MEANS Original Filed April 27, 1933 6 Sheets-Sheet 4 June 4,1940.

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I37 C 4% nw a m m a I kkbik NM 0 m M M w m 6 June 4, 1940. R. w. GEORGERECEIVING MEANS 6 Sheets- Sheet 5 Original Filed April 27, 1953 m b NQQM INVENTOR RALPH W. GEORGE 7%? run-(A, ATTORNEY June 1940- R. w.GEORGE hEcmvINe MEANS '6 Sheets-Sheet 6 Original Filed April 27, 1933INVENTOR RALPH W GEORGE BY z I ATTORNEY Reiuued June 4, 1940 PATENTOFFICE RECEIVING MEANS Ralph W. George, Riverhead, N. 1., assignor toRadio Corporation of America, a corporation ,of Delaware Original No.2,035,745, dated March 31, 1936, Se-

rial No. 668,232, April 27, 1933.

Application for reissue February 3, 1940, Serial No. 317.220

37 Claims.

This invention relates to a receiver particularly adapted to relayand/or amplify and/or demodulate signal modulated carriers of the orderof 70 centimeters in wave length or 428 megacycles in frequency. Theinvention is general, however, and is in no way limited to this definitevalue of wave length. My receiver demodulates carriers modulated in anyof their characteristics, as for example, frequency or amplitude, orboth simultaneously. For example, to obtain secret signalling I may keya tone (in code) giving frequency modulation at the transmiter for dots,and key another tone at the transmitter giving amplitude modulation fordashes. The receiver is of the superheterodyne type. The demodulator mayutilize a standard first detector and oscillator or may use aself-oscillating first detector of 70 centimeter waves. Preferably theself-oscillating detector is of the Barkhausen type giving an 'outputintermediate frequency of, say, 5.0 megacycles plus and minus themodulation frequency. The intermediate frequency amplifier is designedto amplify the band of frequencies between 4.7 and 5.3 megacycles, thetotal band being approximately 600 kilocycles wide. When frequencymodulation is to be demodulated the system is broadly of the artificialline type similar to that disclosed in United States application SerialNo. 618,154, filed June 20, 1932, in which amplitude modulation iseliminated from the output. Provision is made whereby the system mayceive amplitude modulated waves.

The present system includes numerous novel,

features. The present receiver includes a novel and more effectivemethod of coupling the intermediate frequency output of the Barkhausendetector to the intermediate frequency amplifier. This is accomplishedaccording to my invention by using the by-pass condenser in theBarkhausen oscillator circuit as the coupling impedance between the saidoscillating detector and the pri-. mary of the first intermediatefrequency transformer. The by-pass condenser is of such a value that ittunes the primary circuit of the intermediate frequency transformer tothe intermediate frequency. 7 Another feature of the present inventionis in the intermediate frequency transformers which are arranged to passa frequency band 600 kilocycles wide, permitting the use of greaterfrequency modulation which'is desirable, especially in the event thereis present 10 or 20 kilocycles of spurious modulation. This intermediatefrequency amplifier passes a band of sufiicient width to make its use intelevision desirable. The inalso retermediate frequency amplifier iscoupled by one path which includes phase shifting means and phasereversal means to the grids of a pair of detector tubes in phaseopposition, and over another path by way of a coupling tube'-cophasallyto the electrical center of the input circuit.

In a modification increased efficiency is obtained by coupling thecophasal signal to the cathodes of the two detector tubes by way of acapacitive coupling instead of to the center tap of the input circuit.

The latter novel feature is further modified by directly coupling theanode of a coupling tube cophasally to the cathodes of the pair ofrectifiers,

An advantage gained by the use of my novel system in the reception ofultra high frequencies with frequency modulation is that the amplitudemodulation caused by mechanical vibration of a high frequencyoscillating detector is balanced out in the succeeding stages of thereceiver.

Furthermore, practice has taught me that the tube hiss originating inthe first detector, whether of the self-oscillating Barkhausen type, asshown, or of the non-oscillating Barkhausen type using a separateheterodyne oscillator, is largely of amplitude modulation and thus isbalanced out to an appreciable extent. It is also known that hissoriginating in tubes at lower frequencies is likewise composed ofappreciable amplitude modulation, however in the described receiver, byfar the largest value of tube hiss comes from the first detector. Thenovel features of my invention have been set forth in the claimsappended hereto, as required by law.

The nature of my invention and the mode of operation of the same will bebest understood by the following description and therefrom when read inconnection with the attached drawings, in which:

Figure 1 is a circuit diagram of a receiving system of the beat notetype by means of which ultra short waves modulated in frequency or inamplitude may be received, amplified and demodulated;

Figure la. showsa detail of the circuit of Figure 1;

Figures 117, 2 and 3 show modifications of certain portions of thesystem of Figure 1;

Figures 4, 5, 6 and '7 are curves and vector diagrams which help toillustrate the operation of the system; while,

Figure 8 shows a modification of a portion of the circuit of Figure 1.

' ing capacity TC, asshown, acts as a self-oscillating detectoroperating at a frequency determined in part by the capacity TC, when theanode and grid are energized by sources of direct current as shown.

The intermediate frequency amplifier is composed of six intermediatestages IF including six transformers T to Ts inclusive, each enclosed ina separate shield S to Ss inclusive and connected in cascade by thetubes l', 2, I, I, and 5.

Each transformer is enclosed in a shield, as

shown, and energizing leads include the necessary filtering chokes andby-passi.ng condensers to shunt radio frequency currents around thesources for the plates, screen grids, and cathode leldl- 1 5 Thesecondary winding of the final intermediate frequency transformer Ts isconnected, as shown, to the control grid of a tube 6 and also to thecontrol grid of a coupling tube Ill. The anode of the tube l is coupledby a capacity 20, as shown, to the electrical center of the inductanceI. connected between the control grids of the tubes I and 9 in abalanced demodulator stage.

The anode of the tube II is coupled by way of a phase shifting line L1,Ca, CB, In enclosed in shield So to the control grid of a tube I. Theanode of tube I is coupled by the primary winding PW of a phase changingtransformer PC in shield 81 to the inductance 30 which may be consideredthe secondary of this transformer. The primary winding of eachtransformer described hereinbefore is separated by an electrostaticshield SS from the secondary winding. All intermediate frequencytransformers including the phase changing transformer PC are identicalin constants and tuning adJustment. Both the primary and secondarywindings have fairly high inductance, say, 35 microhenrys each, to giveas high an impedance as practical and thus increase the gain. Thewindings and tuning condensers are damped sumcientiy with theresistatice across them to fiatten the double hump frequency responsecharacteristic obtained by closely coupling the primary and secondary,as shown in Figure 4. In Figure 5 I have shown the overall frequencyresponse of the intermediate frequency amplifier stages and the phasechanging transformer including the artificial line in shield So.

The phase shifting line or artificial line in shield may include theessential elements as shown in Figure 1 or the elements as shown indetail in Figure 1a.

The phase shifting line is of conventional low pass filter design togive the desired phase shift of at the grids of the detector tubes 8 andI with respect to the cophasal voltage applied through tube 6. The phaseshifting line consists essentially of the elements 01, L1, Ca, 1a, 0:and the characteristic impedance R1. The condenser CB is an addedblocking condenser and the resistances R1 and R: are respectively usedto supply grid current to the tube and plate current to tube II. Inorderto obtain maximum is degrees.

impedance, C1 is by the capacity of the plate of tube II and the straycapacities of the leads to ground as shown in Fig. 1. Likewise, C: isreplaced by the capacity of the grid of tube I to ground and a smallcondenser in parallel as shown in Figure 1. Ci andC: areshown in dottedlines to indicate this. In operation, the phase shifting line acts asatransmission line of fixed'physical length, and is designed to have anelectrical length of one-quarter wave at 5 megacycles, thus giving acorresponding time delay of wave propagation of 90 degrees from theplate of tube ID to the grid of tube 1. Itis well known that in thistype of artificial line, phase grees. fact, an advantage in this case asit is cumulative with that occurring in the phase changing transformer,thus giving slightly better sensitivity of the frequency modulationdetector. Since, in the phase changing transformer, the ideal conditionof plus and minus 90 degrees phase change with modulation is notrealized. the additional plus and minus 4% degrees is of some value. Inpractice, of course, the above stated values are not necessarily used.The phase changing transformer is essentially one section of a band passfilter with a flat frequency response characteristic as shown in Figure4. This characteristic is obtained by tuning the primary and secondaryindependently of each other to 5 megacycles, then closely coupling thetwo tuned circuits to give the necessary coupling coefficient ofapproximately 12% and the addition of the damping resistances which areapproximately 30% higher in value than the characteristic impedance ofthe filter. The above procedure is common practice in dealing with suchtypes of band pass filters. It is well known that in a band pass filterembodying a fiat frequency response characteristic there occurs a phaseshift proportional to frequency over the fiat part of thecharacteristic; at the lower frequency the phase shift is zero; atthe'mid-band frequency it is 90 degrees; and at the higher frequency itI have drawn a broken curve in Figure 4, showing approximately the phaseshift with frequency. It will be seen that the useful phase change isabout plus and minus 70 degrees; hence, the additional cumulative phaseshift occurring in the phase shifting line, previously mentioned, isadvantageous in securing maximum sensitivity to frequency modulation.This fact can be readily seen from the vector diagrams in Figure '7.

As has been stated before, the IF transformers are identical in alldetails with the phase chang-- ing transformer, with the exception ofthe midtap on the secondary of thelatter, and it follows 5% whichamounts to plus and minus 4% de- 1 This phase shift with frequency is,in'

that there will be a similar phase shift with its- The band or signalcarrying intermediate fre quencies is passed through the intermediatefrotion, made to be as purely capacitive as possible, and still retain areasonable impedance to effect a 90 degree phase shift from the gridvoltage to the output voltage applied cophasally from the anode of C byway of capacity 20 to the electrical center of the'inductance 30connected to the detector grids. This capacitive impedance serves alsoto eliminate possible phase shift of the intermediate frequency due tofrequency shift in this circuit. Tube i feeds an artificial line- L1,In, C: which gives relatively a 90 degree phase shift of the voltage ofthe oscillations at the anode of tube I as compared to the voltage ofthe oscillations on the grid of tube Ill. The phase shifted oscillationsin the output of tube I are fed into the phase changing transformer PCin shield 31. The phase changing transformer produces approximately anadditional 90 degree phase shift in the voltages of the oscillations,which phase shift is cumulative at the mid-band of the passed frequency.The result is that the band of signal carrying oscillations is feddifferentially to the grids of the detector tubes 8 and 9 and to saidgrids 90 degrees out of phase with respect to a component of the signalwhich is fed cophasally to the grids of said tubes. The plates of thedetectors 8 and 9 are connected in push-pull by transformer F1 and jacks22 for frequency modulation detection and in parallel by transformer ATand jacks 24 for amplitude detection. Signals resulting fromdemodulation of amplitude modulated signals will appear in a circuitconnected with Jack 24 while signals resulting from frequency modulationwill appear in a circuit comiected to Jack 22.

Jacks II and II are provided for the connection of plate current metersas shown. These meters are necessary in adjusting the receiver and arean aid in tuning. The following conditions can be obtained by their aid.The detector tubes 8 and 9 must be balanced and, their bias properlyadjusted for ordinary bias detection; the cophasal and antiphasalsignals impressed on the grids of tubes 8 and 9 must be adjusted to beequal for maximum sensitivity to conform to Figure I; and in tuning, theIF must be at the mid-band frequency which is indicated by equal platecurrents as can be seen in Figure 6.

Actually, both'demodulated amplitude and frequency types of modulationappear in each plate circuit.

More in detail, the operation of the device is as follows: Ultra highfrequency signal carrying oscillations are converted by the oscillatingdetector I in stage B0 to a high intermediate frequency. Theintermediate frequency produced in I is taken from the control grid sideof the Barkhausen circuit by a lead 26 and fed through the primarywinding of the first intermediate transformer T. The total capacitiesconnected between the grid and ground, including mainly the by-passcondenser 28 between the plate and grid of the Barkhausen circuit, areso adjusted as to tune the intermediate frequency transformer primary toresonance at the intermediate frequency. Thus, the by-pass condenser 28serves two main purposes. It acts as a by-pass path in the Barkhausenoscillating detector circuit to shunt the high frequency oscillations insaid circuit around the energy sources and serves also for tuning theintermediate frequency output circuit, giving mavimum coupling betweenthe detector and the intermediate frequency amplifier at theintermediate frequency. Any slight variation in the capacity of theBarkhausen tuning condenser necessary to tune the Barkhausen oscillatorhas a negligible effect on the total capacity which tunes theintermediate frequency output circuit. The signal carrying intermediatefrequency band is amplified in the intermediate frequency amplifier andfed cophasally to the coupling tubes 6 and Ill. Since it is thought thatthe use of a definite frequency to illustrate the invention will makethe same more clear, it is assumed that the intermediate frequency is 5megacycles plus and minus 300 kilocycles. Applicant is not, however,limited to such frequencies since obviously others may be used. Tube 6is coupled to the electrical center of the inductance "30 between thegrids of the detector tubes 8 and 9, thus feeding the detector gridscophasally with signal voltages substantially 90 degrees out of phasewith the signal voltages at the grids of tubes 6 and I0. Tube i0 feedsthrough the artificial line or other phase shifting circuit in Se,coupling tube 1 and the phase changing transformer PC, the gridelectrodes of the detectors 8 and 9 differentially phased signal, thevoltage of which is substantially 180 degrees out of phase, and inphase, at the mid-band frequency, with respect to the voltage of thesignal at the grid of tube it). These voltages fed to the grids of tubes8 and ill therefore are plus and minus 90 degrees out of phase withrespect to the voltage of the signal fed cophasally from 6 to the gridsof 8 and HI as shown by the vector in Figure 7. More in detail, it weconsider the various voltages applied to the grids of tubes 8 and lvectorally we will have a resultant voltage Eg' and E 9 on the gridswhen ED9=the differentially phased component. Ec=the cophasal component,and 0, the phase, is less than 90 degrees. Thus, at the mid-bandfrequency, the plate currents of the two detector tubes are equal.However, when the frequency increases to 5.3 megacycles (maximum), theinherent phase change with frequency change in the phase changingtransformer gives a phase change of the differentially fed signalapproaching 90 degrees as a satisfactory operating limit, in which casethe phase of the differentially fed signal on the grid of tube I isalmost in phase with the cophasally fed signal, as shown in the seconddiagram of Figure 7, and the phase of the differentially fed signal onthe grid of tube 9 is almost 180 degrees out of phase with thecophasally fed signals. The conditions are reversed when the signalfrequency approaches 4.7 megacycles, the lower frequency limit of theband. The resulting differential plate current characteristic is shownby the curve in Figure 6 and converts the frequency modulations intoamplitude changes when utilized by the audio transr former connected inpush-pull to the output electrodes of tubes I and l. The operation of abalanced modulation detector of this type has been explained in UnitedStates application Serial No. 618,154, filed June 20, 1932. A briefstatement of the manner in which the frequency modulations-are convertedinto amplitude variations when taken with the vectors of Figure 'l 8 tothe detector.

'direction will take place.

It can be shown vectorally, as illustrated in the first diagram ofFigure '1 that these differentially and cophasally applied potentialswill,

when combined. produce a resultant voltage on e grids of tubes. and 8which can be shown Ebe 90 degrees out of phase. These resultant ltageswill produce a steady fiow of current in the output circuits of each oftubes 8 and 8. Since the output circuits of tubes 0 and a are connectedin push-pull for frequency modulation, the energies from the two tubesadd and produce a resultant energy characteristic of the sum of theenergies. Frequency modulation causes the plate currents of the twodetector tubes to vary differentially and according to the frequencymodulation; this variation is utilized by the push-pull transformerconnection; amplitude modulation appears equally in both tubes andthereby is cancelled in the push-pull transformer connection.

Now assume that the frequency of the oscillations passed by theintermediate frequency amplifier increases due to frequency modulation.The voltages applied to the control grids of the tubes 8 and 9 by thecophasal connection and by the phase opposition coupling will beshifted, as indicated by the second vector diagram in Figure I. Thevoltages applied in phase opposition will still be 180 degrees out ofphase with respect to each other but will be shifted in the spectrumwith respect to the voltages applied by the oscillations in phaseopposition when the frequency of the waves was at the midpoint of theintermediate frequency amplifier, as illustrated in diagram No. l ofFigure 7. This shifting of the frequency will. as shown vectorally inthe second diagram of Figure I, produce new resultants on the grids oftubes 8 and 8 respectively. These resultant voltages are of differentamplitude and cause anode currents of different amplitude to flow in theoutput circuits, as illustrated in the diagram of Figure 6. Theamplitude of the combined resultants in the output circuit, of course,changes.

In like manner it has been shown vectorally in Figure 7 anddiagrammatically in Figure 6 that if the frequency of the waves passedby the intermediate frequency amplifier shifts to a value below themidpoint of the intermediate frequency amplifier, a shift of the vectorsin an opposite This shift produces resultants of different voltage onthe control grids of tubes 8 and 9 and therefore causes said tubes topass different values of anode current. In the above manner thefrequency modulation of the high fr ncy carrier is caused to produceamplitu variations in current characteristic of the signal modulations.

In Figure 1b 1 have shown a modified means for applying the cophasalsignals from the tube As shown the amplified oscillations may be appliedfrom the output of tube 8 to a separate element such as an extra controlgrid E6 in each of the tubes instead of to the cathodes or to thecontrol grids fed by the phase changing transformer. The advantage isobvious in view of the possible higher capacitive reactance of suchseparate grid elements.

If the oscillations at'intermediate frequencyareappliedbywayoi'thecoupling tubeicophasally to the cathodes of thetubes increased emciency is obtained.

An additional circuit by means of which the oscillations may be appliedcophasally to the cathodes is illustrated in Figure '2. In Figure 2landlthe elements shown may replace the intermediate frequencytransformer enclosed in the shield 85, the coupling tube 8, theartificial line enclosed in the shield St, the tube II, the tube 1, andthe phase shifting transformer PC and the detector tubes 8 and 8. InFigure 2 the anodes of the tubes have been shown as being coupled inpush-pull relation for the reception of frequency modulated waves.Obviously, I contemplate a parallel connection of the anodes of thesetubes to receive amplitude modulated waves.

In Figure 3 I have shown a modified form of the circuit of Figure 2. Thecircuit of Figure 3 may replace the same elements which the circuit ofFigure 2 may replace,as set forth above.

Figures 2 and 3 show two circuit variations in the phase shiftingtransformer coupling tube 8 and balanced modulator detectors 8 and 8which do not change the fundamental principles of operation but improvethe coupling of the cophasally fed signal to the detector. The circuitof Figure 2 is the same as the corresponding portion of the circuit usedin the embodiment described in connection with Figure 1 with theexception that the cophasal signal is fed to the cathodes 50 and 60 ofthe detectors 8 and 8 instead of to the center tap on the inputinductance 38. This results in approximately 50 percent more cophasalvoltage impressed on the detector, and simplifies the practicalarrangement of the circuit as shown.

In Figure 3 I have shown a direct coupled arrangement for feeding thecophasal signal from the plate of the coupling tube 6 to the cathodes 58and ill of the detectors 8 and 8. The circuits of Figures 2 and 3 areotherwise similar to the corresponding parts of Figure 1 except that inthe circuit of Figure 3 the filament heating leads include radiofrequency chokes as shown, the purpose of which is to reduce thecapacity between the tube elements and ground.

Apparent advantages are, simplification of the circuit, and maximumcophasal signal voltage on the cathodes ill and 68 of the detectors 8and 8. A further refinement of the circuit of Figure 3, which wouldapply to the circuit of Figure 1, is shown in the use of chokes in eachside of the filament or heater leads. This greatly reduces the capacitybetween the cathode and ground and results in an increase in thecapacitive impedance to ground of the cophasal coupling circuit whichincreases the cophasal signal voltage impressed on the cathodes.

It is also obvious that, in order to get the desired phase relationbetween the cophasal and difierential phased signal at the detectors 8and 8, any method of phase shifting or phase adiustment that is knownand is suitable may be used. Such phase adjustment need not necessarilybe made in the portion of the circuit in which the artificial line isplaced, that is, in the unit enclosed in St, but it may be placed in anyother part of the circuit to accomplish the desired phase adjustment,such as in the cophasal coupling circuit.

It is also conceived that the first detector is not limited to theBarkhausen type, but it may be similar to first detectors insuperheterodyne circuits already in use.

It is further conceived that under some conditions the intermediateamplifier will not be of the anode energizing leads, choking inductancesand radio frequency by-pass condensers to prevent ultra high frequencyoscillations dealt with in the receiver and the high frequencyoscillations dealt with in the intermediate frequency amplifier fromreaching the energizing sources and reacting therein to'produce unstableoperation of the device. Each element of the receiver is, as shown,included in a separate grounded shield to electrically isolate thecircuits of the several elements to prevent reaction there'- between.The transformer windings of the various intermediate frequencytransformers and of the phase changing transformers are separated asshown by electrostatic shields SS, which may be of the type covered byUnited States application No. 598,731, filed November 3, 192 2, maturedinto Patent #l,942,578, on January 9, 1934.

Where signals modulated in frequency by a keyed tone to produce oneelement of a signal and simultaneously modulated in amplitude'by anotherkeyed tone to produce another signal element for secrecy purposes, aretransmitted, the receiver of Figure 1 may be niodified in its circuitsassociated with the output electrodes of detectors 8 and 9 as indicatedin Figure 8. Amplitude modulated signal elements could be separated outfrom thefrequency modulated signal elements by the parallel transformersPT and appear in any indicating device plugged into Jack ll]; Theelements represented by frequency modulated waves will be separated outin transformer F1 and appear in an indicating device plugged into jack2. Y

Having thus described my invention and the operation thereof, what Iclaim is:

1. Means for receiving signal modulated oscillations of ultra highfrequency comprising, an oscillating detector having a frequencydetermining circuit connected between its control grid andanode.-a"capacity by-passing said frequency determining circuit, saidby-passing capacity tuning said circuit to the beat frequency producedin said oscillating detector due to reaction between the signal wave andoscillations produced in said detector, an intermediate frequencyamplifier coupled to said by-passing capacity, rectifying means, and aplurality of paths coupled between said intermediate frequency amplifierand said rectifying means, one of said paths including phase shiftingmeans.

2. A circuit for receiving signal modulated oscillations of ultra highfrequency comprising, an oscillating triode having control grid, anodeandcathode, and a frequency determining circuit connected between itscontrol grid and anode and to said cathode, means for impressing asignal wave on said triode, a capacity by-passing said frequencydetermining circuit, said bypassing capacity tuning said circuit to thebeat frequency produced in said oscillating detector 'due to reactionbetween signal wave and oscillations produced in said detector, anintermediate frequency amplifier coupled to said by-passing capacity andtuned to the beat frequency, detectand a plurality of paths'coupiedbeintermediate frequency amplifier on the one hand and to like inputelectrodes of said thermionic tubes on the other hand, and a couplingtube having its input electrodes coupled to said intermediate frequencyamplifier on the one hand and its output electrodes coupled to said likeinput electrodes in said pair of thermionic tubes on the other hand.

4. A circuit for demodulating ultra high frequency waves including anoscillating detector comprising, a thermionic tube having its input andoutput electrodes coupled by a frequency determining circuit and toradiant energy absorbing means, an intermediate frequency amplifier, acapacitive coupling between said amplifier and said oscillatingdetector, a pair of thermoinic tubes each having a control electrode andan output electrode, a phase shifting circuit coupled to v saidintermediate frequency amplifier on the one hand and to a controlelectrode in each of said thermionic tubes on the other hand, a couplingtube having its input electrodes coupled to said intermediate frequencyon the one hand and its output electrodes coupled to a control electrodein each tube of said pair of thermionic tubes on the other hand, andcircuits connecting the output electrodes of said tubes either inparallel or in push-pull.

5. The method of demodulating frequency modulated high frequencyoscillatory energy which includes the steps of, reducing the frequencyof said modulated oscillatory energy, amplifying said oscillatory energyof reduced frequency, dividing said amplified oscillatory energy intotwo portions each of which portions includes energy of the mean carrierfrequency and side band frequencies, producing a phase shift in theoscillatory energy of one of said portions, said produced phase shiftbeing for the oscillatory energy of said portion of the mean frequency,producing a phase shift of the oscillatory energy in said other portion,the phase shift produced in said last portion being substantially aphase reversal of the oscillatory energy of said last named portion ofthe meanfrequency, and differentially combining said last namedoscillatory energy with the oscillatory energy in said one of saidportions to produce a resultant.

6. The method of demodulating signal carrying ultra high frequencyoscillatory energy which includes the steps of beating said oscillatoryenergy with other oscillationsto reduce the frequency of saidoscillatoryenergy, amplifying said oscillatory energy of said reducedfrequency, dividing said amplified oscillatory energy into two portions,producing a phase shift in one of said portions, said produced phaseshift being substantially 90 for the oscillatory energy of said portionof the mean frequency, producing a phase shift of the oscillatory energyin the other of said portions, the phase shift produced in said ingmeans comprising, a thermionic tube having i an input circuit responsiveto said oscillations and an output circuit, a pair of thermionicdetectors having input electrodes, a phase shifting circuit coupling theoutput circuit of said first named tube in-phase opposition to the inputelectrodes of said thermionic detectors, a second ther mionic tubehaving an input circuit responsive to said oscillations, said secondthermionic tube having an output circuit, and a circuit coupling theoutput circuit of said second named tube cophasally to the inputelectrodes of said detectors.

8. Signal demodulating means comprising, a source of signal modulatedoscillations, a pair of thermionic detector tubes each having an inputelectrode and an anode, circuits connecting the anode electrodes of saidtubes in push-pull relation, a thermionic coupling tube having an inputelectrode and an output electrode, said tube having its input electrodecoupled to said source of oscillations, means for coupling the outputelectrode of said last named tube differentially to the input electrodesof .said detector tubes including, a phase shifting circuit and a phaseshifting transformer, an additional thermionic tube having input andoutput electrodes, said additional tube having its input electrodescoupled to said source of oscillations, and a circuit coupling theoutput electrodes of said additional tube cODhasally to the inputelectrodes of said detector tubes.

9. In a signal demodulating means to be used with a source of signalmodulated oscillations, a pair of thermionic detector tubes each havingan anode, a cathode and a control grid, a circuit connecting thecathodes and anodes of said tubes in push-pull relation, a thermioniccoupling tube having input electrodes and output electrodes, said tubehaving its input electrode coupled to said source of oscillations, meansfor coupling the output electrodes of said last named coupling tubedifferentially to the control grids of said detectors, said meansincluding a phase shifting circuit and a phase shifting transformer, anadditional thermionic coupling tube having input electrodes and outputelectrodes, a circuit coupling the input electrodes of said additionaltube of said source of oscillations, and a circuit coupling the outputelectrodes of said additional tube cophasally to the cathodes of saiddetector tubes.

10. An arrangement as recited in claim 9 in which the output electrodesof said additional tube are directly coupled to the cathodes of saiddetector tubes.

11. Signal demodulating means to be used with a source of oscillationssimultaneously varied ating of said transformer, a second transformerhaving a pair of primary windings and a secondary winding, circuitsconnecting said primary windings in parallel with the anode-to-cathode'impedances of said tubes, and means for the con-, nection of anindicator with the secondary winding of said last named transformer.

12. Signal demodulating means comprising, a source of signal modulatedoscillations of constant amplitude, a pair of thermionic tubes eachhaving an anode and a cathode and a plurality of control gridelectrodes, a reactance having one terminalconnected to a control gridin one of said tubes and the other terminal connected to a control gridin the other of said tubes, a circuit connecting a point on saidreactance to the cathodes of said tubes, a circuit connected to saidsource and coupled to saidireactance for applying signal modulatedoscillations in phase opposition from said source to said control gridsby way of said" reactance, a circuit connecting another control grid ineach tube together and to the tube cathodes by way of a commonimpedance, and a circuit connecting said source of signal modulatedoscillations to said impedance for applying signal modulatedoscillations cophasally to said other control grids in said tubes.

13. Frequency modulated oscillation demodulatlng means comprising, athermionic tube having an input circuit responsive to said oscillations,said tube also having an output circuit, a pair of thermionic detectorseach having an input electrode, a phase shifting network comprisingseries inductances separated by a series capacity connected in theoutput circuit of said first named tube, means for coupling said phaseshifting network in phase opposition to the input electrodes of saidthermionic detectors, a second thermionic tube having an input circuitresponsive to said frequency modulated oscillations, said second tubealso having an output circuit, and a circuit coupled to the outputcircuit of said last named tube and to the input electrodes of saiddetector for.

applying said oscillations from the output circuit of said last namedtube cophasally to the input electrodes of said detectors.

14. A circuit for demodulating ultra high frequency waves modulated inamplitude and in frequency including, radiant energy absorbing means, anoscillating detector comprising, a thermionic tube having input andoutput electrodes, a frequency determining circuit coupling saidelectrodes together and to said radiant energy absorbing means, anintermediate frequency amplifier, capacitive means coupling saidintermediate frequency amplifier to said oscillating detector, a pair ofthermionic detector tubes having input electrodes and output electrodes,a phase shifting circuit coupled between said intermediate frequencyamplifler and the input electrodes of said thermionic detectors, saidphase shifting circuit including inductances in series separated by aseries capacity and a parallel capacity, a coupling tube having inputelectrodes and output electrodes, means coupling said input electrodesto said intermediate frequency amplifier, means coupling the outputelectrodes of said coupling tube to the input electrodes of said pair ofthermionic tubes, a plurality of transformers, one of said transformershaving a single primary winding and the other of said transformershaving a pair of primary windings, circuits connecting the outputelectrodes of said tubes in push-pull relation through the primarywinding of said transformer having a single primary winding, circuitsconnecting the output electrodes of said tubes in parallel through theprimary windings of said transformer having a pair of primary windings,and means for connecting means with the secondary windings of each ofsaid transformers.

15. A device for converting signal modulated oscillations of an ultrahigh frequency into characteristic signal modulated oscillations oflesser frequency comprising, an electron discharge device having ananode, a cathode and a control electrode, a conductor connected to thecontrol electrode of said tube. a conductor connected to the anode ofsaid tube, a circuit for maintaining the control electrode of said tubeat a high positive potential with respect to the anode and cathode ofsaid tube whereby oscillations are produced in said tube, a condenserconnected between said conductors to tune the circuit formed by saidconductors and said condenser to a frequency equal to the frequency ofthe signal wave plus or minus the frequency to which it is desired toconvert the signal carrying ultra high frequency oscillations, a circuitfor impressing the ultra high frequency signal modulated wave on saidconductors, and a second condenser connected across said conductors atpoints spaced from said first named condenser, said second namedcondenser serving to tune the circuit formed thereby and by the othercondenser and conductors to the lower frequency desired, to by-pass theultra high frequency oscillations and to couple said circuit to a load.

16. In combination in an ultra high frequency wave receiving system, abipolar antenna tuned to the incoming signal wave, an ultra highfrequency oscillating demodulator of the beat frequency type forproducing an intermediate frequency, said oscillator comprising, anelectron discharge device having an anode, a control electrode and acathode, and having means for maintaining the control electrode at ahigh positive potential relative to the cathode and anode, a pair ofLecher wires connected to said anode and control electrode, a tuningcondenser connected across said Lecher wires, said antenna being coupledto said Lecher wires through blocking con- I densers, an additionalcondenser connected across mlonic tube having input and outputelectrodes,

said input and output electrodes being coupled together by a frequencydetermining circuit and connected to said radiant energy absorbingmeans, an intermediate frequency amplifier, ca-

pacitive means coupling said intermediate frequency amplifier to saidoscillating detector, a pair of thermionic detector tubes each having acontrolling electrode and an anode, a phase shifting circuit coupled tosaid intermediate frequency amplifier on the one hand and to acontroling electrode in each of said thermionic detectors on the otherhand, said phase shifting circuit including inductances in series and aparallel capacity, a coupling tube having input electrodes and outputelectrodes, means coupling said input electrodes to said intermediatefrequency amplifier and said output electrodes to a controllingelectrode in each tube of said pair of thermionic tubes, a plurality oftransformers each having a primary winding and a secondarywinding, acircuit connecting the anodes of said pair of tubes in push-pullrelation through the primary of one of ing the degree of modulationthereon, dividing.

said oscillatory energy into two' portions, producing a phase shift inthe energy of-one of said portions such that there is a phase quadraturere lation between the energies in said respective portions, anddiflerentially combining the energies to render the signal.

19. In a signal demodulating system to be used with a source of signalmodulated oscillations, a pair of thermionic detector tubes each havinga control grid, a cathode and an anode, output circuits connected withthe anodes of said tubes, a thermionic coupling tube having input andoutput electrodes, a circuit connecting the input electrodes of saidcoupling tubes to said source of signal modulated oscillations, areactance connecting the control grids and cathodes of each of saiddetector tubes in parallel, a circuit coupling the output electrode ofsaid coupling tube to said reactance, said last named circuit includingphase shifting means, an additional coupling tube having inputelectrodes and output electrodes,'a circuit connected with the inputelectrodes of said additional coupling tube, said circuit being coupledto said source of signal modulated oscillations, a phase shiftingcircuit comprising series inductances and parallel capacitancesconnected between the output electrodes of said additional couplingtube, a third coupling tube having input and output electrodes, acircuit connecting the input electrodes of said third coupling tube tosaid phase shifting circuit, and a transformer having a primary windingcoupled to the output electrodes of said third coupling tube, and asecondary winding connected between the control electrodes of said pairof thermionic detectors.

20. In a system for demodulating wave energy the frequency of which hasbeen modulated in accordance with signals, acircuit on which said waveenergy the frequency of which has been modulated is impressed, a pair ofelectron discharge systems each having input and output electrodes, autilization circuit coupled with said output electrodes, an inputcircuit tuned substantially to the mean frequency of said modulated waveenergy connected to the input electrodes of said electron dischargesystems, said input circuit including an inductance, a first frequencymodulated wave energy path having an input coupled to said firstcircuit, said first path including an inductance inductively coupled tosaid first named inductance, said first path serving to transferfrequency modulated wave energy from said first circuit to saidinductance in said tuned circuit, and a second frequency modulated waveenergy path including a condenser having one terminal coupled to saidfirst circuit and another terminal coupled to a point intermediate theterminals of said first inductance to also transfer frequency modulatedwave energy from said am circuit to the input electrodes of saiddischarge systems.

21. A system as recited in claim 20 wherein said inductance in saidinput circuit is shunted by a resistance to broaden the responsecharacteristic of said input circuit with respect to the frequencymodulated wave energy.

22. In a system for demodulating frequency modulated wave energy,heterodyning means for reducing the frequency of said frequencymodulated wave energy, means for amplifying the frequency modulated waveenergy of reduced frequency, a circuit on which said amplifier frequencymodulated wave energy of reduced frequency is impressed, a pair ofrectifier systems each having input and output electrodes, an outputcircuit connecting said output electrodes in push-pull relation, a firstpath for transferring voltages characteristic of the frequency modulatedwave energy from said first circuit in phase opposition to the inputelectrodes of said rectifier systems comprising a tuned reactanceconnecting the input electrodesof said rectifier systems in push-pullrelation, a second tuned reactance coupled to said first named tunedreactance, and a coupling between said second tuned reactance and saidfirst circuit,- and a second path for transferring voltagescharacteristic of said frequency modulated wave energy from said firstcircuit to the input electrodes of said rectifier systems comprising acapacity having one terminal coupled to said first circuit and a secondterminal coupled by similar conductors to said input electrodes.

23. A system as recited in claim 22 wherein one of said tuned reactancesis shunted by a resistance to widen its response characteristics withrespect to said frequency modulated wave energy.

24. In a system for demodulating frequency modulated wave energy, asource of frequency modulated'wave energy, a pair of electron dischargetube systems each having input and output electrodes, an output circuitconnected with said output electrodes, an inductance tuned to the meanfrequency of said wave energy connecting the input electrodes of saiddischarge tube systems in push-pull relation whereby voltages induced insaid inductance are impressed in phase opposition on said inputelectrodes, a second inductance coupled to said first inductance andmeans for impressing frequency modulated wave energy" from said sourceon said second induct-'- ance, a condenser having two terminals, meanscoupling one terminal of said condenser to an input electrode in each ofsaid systems and means connecting the other terminal of said condenserto said source of frequency modulated wave energy whereby voltagescharacteristic of said frequency modulated wave energy are transferredby said condenser from said source to said input electrodes insubstantially like phase.

25. A system as recited in claim 24 wherein at least one of saidinductances is shunted by a resistance to broaden the resonancecharacteristic of said tuned circuit.

26. In a system for demodulating frequency modulated wave energy, acircuit on which said frequency modulated wave energy is impressed, apair of electron discharge devices each having a control grid, acathode, and an anode, an output circuit connecting said anodes andcathodes in push-pull relation, a first path for transferring frequencymodulated wave energy from said first circuit in phase opposition to thecontrol anus grids and cathodes of said discharge devices,

-said first path comprising a tuned reactance connecting the controlgrids and cathodes of said devices in push-pull relation and a secondtuned reactance coupled to said first named tuned reactance, and aconnection between said second tuned reactance and said first circuit,and a second path for transferring frequency modulated wave energy inlike phase to the input electrodes of said discharge devices comprisinga capacity having a terminal coupled to said first circuit and having asecond terminal coupled to said control grids by substantiallyequivalent conductors.

27. A system as recited in claim 26 wherein at least one of said tunedreactances is shunted by a resistance to broaden the resonancecharacteristic thereof.

28. In a system for demodulating frequency modulated wave energy, acircuit on which said frequency modulated wave energy is impressed, apair of electron discharge tubes each having a plurality of controlelectrodes, an anode, and a cathode, an output circuit connected withsaid anodes and cathodes, a first path for transferring frequencymodulated wave energy from said first circuit in phase opposition to thecorresponding control electrodes in said tubes comprising a tunedreactance connecting a corresponding electrode in each of said tubes ina push-pull circuit, a second reactance coupled to said first namedtuned-reactance, and a connection between said second reactance and saidfirst circuit, and a second path for transferring modulated wave energyin phase to other corresponding control electrodes in said tubescomprising a capacity having a terminal coupled to said first circuitand having a terminal connected by electrically equivalent conductors tosaid other corresponding control electrodes in said tubes.

29. A system as recited in claim 28 wherein at least one of said tunedreactances is shunted by a resistance to broaden the resonancecharacteristic thereof.

30. In a system for demodulating frequency modulated wave energy, animpedance on which the frequency modulated wave energy is impressed, apair of detector tubes each having an anode, a cathode, and a controlgrid, an output circuit connected with said anodes and cathodes, aninductance tuned to the mean frequency of said wave energy connectingthe control grids of said tubes in push-pull relation whereby voltagesinduced in said inductance are impressed in phase opposition on saidcontrol grids, a second inductance coupled to said first inductance andmeans for impressing frequency modulated wave energy from said source onsaid second inductance, a condenser having one terminal connected to thecathode of each of said tubes, and means connecting the other terminalof said condenser to said source of frequency modulated wave energywhereby voltages characteristic of said frequency modulated wave energyare transferred by said condenser submantially in phase on saidcathodes.

31. In a system for demodulating wave energy the frequency of which hasbeen modulated in accordance with signals, a circuit on which said waveenergy the frequency of whichhas been modulated is impressed. a pair ofelectron discharge rectifier systems having input and output electrodes,a utilization circuit coupled with said output electrodes, a parallelcircuit having inductance and'capacity tuned to the mean frequency ofsaid modulated wave energy connected between input electrodes of saidelectron discharge rectifier systems, a first path coupled to said firstcircuit, said first path including an inductance coupled to theinductance of said tuned circuit, said first path transferring modulatedwave energy to said tuned circuit, and a second path including acondenser connected in said first mentioned circuit and to a pointintermediate the terminals of said tuned circuit to transfer modulatedwave energy from said first circuit to input electrodes of saidrectifier systems. 32. In a system for demodulating frequency modulatedwave energy, a pair of electron discharge rectifier systems having inputand output electrodes, a demodulation output circuit connected with saidoutput electrodes, a circuit on which said frequency modulated waveenergy is impressed, a path for transferring frequency modulated waveenergy from said circuit in pushpull relation to the input electrodes ofsaid rectifier systems, said path including an inductance coupledbetween the input electrodes of said electron discharge rectifiersystems and a second inductance connected to said circuit and coupledinductively to said first inductance, condensers connected in shunt toand tuning said inductances, and a second path for transferringfrequency modulated wave energy from said circuit to said rectifiersystem input electrodes said second path comprising a condenserconnected between said circuit and said input electrodes.

33. In a receiver for receiving and translating frequency modulatedwaves, a pair of rectifier systems each having input and outputelectrodes, a coil connected between and in phase opposition to likeinput electrodes of said rectifiers, a condenser in shunt to said coilfor tuning said coil to the mean frequency of frequency modulated wavesto be detected by said rectifiers, a primary coil, means for feedingfrequency modulated waves into said primary coil, said primary coilbeing inductively coupled to the coil connected between like electrodesof said rectifier system, a condenser connected to an intermediate pointon the coil connected between input electrodes of said rectifiersystems, means feeding frequency modulated waves through said condenserto said first mentioned coil, a demodulation frequency impedanceconnected between andin phase opposition to like output electrodes ofsaid rectifiersystsms, and a signal translating system connected tosaid'impedance.

34. A receiver for frequency modulated waves comprising means forheterodyning received frequency modulated waves to a convenientintermediate frequency, a transformer having a tunedseccndarycoiitnnedtothemeanfrequeney of the frequency modulatedintermediate frequency waves, means for feeding the frequency-modulat-Oil waves 01' intermediate frequency to the primaryof saidtransformerand thereby transferringsaidwavestothetunedsecondarybyvirtueosinductivecoupiinmapairofrectifiersystems each having input and outputelectrodes, means connecting said tuned secondary coil in phaseopposition between and to a pair of like input electrodes of saidrectifiers, a condenser connected cophasally orin push-push to likeinput electrodes of said rectifier systems, means for feeding thefrequency modulated waves of intermediate frequency through saidcondenser in push -push to said like input electrodes, and ademodulation frequency circuit connected in phase opposition between andto like output electrodes of said rectifier systems.

35. A receiver for frequency modulated waves comprising means forheterodyning received frequency modulated waves to a convenientintermediate frequency, a transformer having a condenser tuned primarycoil and a condenser tuned secondary coil tuned to the mean frequency ofthe frequency modulated intermediate frequency waves, means for feedingthe frequency modulated waves of intermediate frequency to the condensertuned primary of said transformer and thereby transferring said waves tothe tuned secondary by virtue of inductive coupling, a pair ofrectifier'systems each having input and output electrodes, meansconnecting said tuned secondary coil in phase opposition between and toa pair of like input electrodes of said rectifiers, a condenserconnected cophasally or in push-push to like input electrodes of saidrectifier systems, means feedng frequency modulated waves thru saidcondenser in push-push to said input electrodes, and a demodulationfrequem; circuit connected in phase opposition between and to likeoutput electrodes of said rectifier systems.

36. In a system for demodulating wave energy the frequency of which hasbeen modulated in accordance with signals, a circuit on which said waveenergy the frequency of which has been modulated is impressed, a pair ofelectron discharge rectifier systems having input and output electrodes,a utilization circuit coupled with said output electrodes, a circuittuned to the mean frequency of ,said modulated wave energy connectedbetween the input electrodes of said electron discharge systems, saidtuned circuit including an inductance, a second inductance coupled tosaid first inductance, a first path coupled to said first circuit, saidfirst path including said second inductance coupled to said first namedinductance, said first path transferr ng modulated wave energy from saidfirst circuit to said inductance and thence to the input electrodes ofsaid rectifier systems in phase displaced relation, and a second pathincluding a connection between said first circuit and a point on andintermediate the terminals of said first inductance to transfermodulated wave energy from said first circuit substantially in phase tothe input elecrodes of said rectifier systems.

37. A system as recited in claim 36 wherein said inductances are shuntedby resistances.

RALPH w. Gnome.

